/*******************************************************************************
 * Copyright (c) 2002, 2008 QNX Software Systems and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 * QNX Software Systems - Initial API and implementation
 * Anton Leherbauer (Wind River Systems)
 * 
 * See org.eclipse.cdt.internal.ui.text.c.hover.SourceViewerInformationControl
 * 
 * This class's contructor has been rewritten to fit the purpose of Photran hover tool-tip
 * The rest of the class remains the same
 *
 * Original Contributors:
 * QNX Software Systems and others.
 * Anton Leherbauer (Wind River Systems)
 * 
 * For Photran:
 * Jungyoon Lee, Kun Koh, Nam Kim, David Weiner (UIUC) - Modification to run on Photran
 *******************************************************************************/
package org.eclipse.photran.internal.ui.editor_vpg.hover;

import org.eclipse.cdt.ui.CUIPlugin;
import org.eclipse.cdt.ui.PreferenceConstants;
import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.preference.IPreferenceStore;
import org.eclipse.jface.preference.PreferenceConverter;
import org.eclipse.jface.resource.JFaceResources;
import org.eclipse.jface.text.Document;
import org.eclipse.jface.text.IDocumentPartitioner;
import org.eclipse.jface.text.IInformationControl;
import org.eclipse.jface.text.IInformationControlCreator;
import org.eclipse.jface.text.IInformationControlExtension;
import org.eclipse.jface.text.IInformationControlExtension3;
import org.eclipse.jface.text.IInformationControlExtension5;
import org.eclipse.jface.text.rules.FastPartitioner;
import org.eclipse.jface.text.rules.ITokenScanner;
import org.eclipse.jface.text.source.ISourceViewer;
import org.eclipse.jface.text.source.SourceViewer;
import org.eclipse.photran.internal.ui.editor.FortranEditor;
import org.eclipse.photran.internal.ui.editor.FortranKeywordRuleBasedScanner;
import org.eclipse.photran.internal.ui.editor.FortranStmtPartitionScanner;
import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.StyledText;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.events.FocusListener;
import org.eclipse.swt.events.KeyEvent;
import org.eclipse.swt.events.KeyListener;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.FontData;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.RGB;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Control;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.Shell;
 

/**
 * Source viewer based implementation of <code>IInformationControl</code>.
 * Displays information in a source viewer.
 */
public class SourceViewerInformationControl implements IInformationControl, IInformationControlExtension, IInformationControlExtension3, IInformationControlExtension5, DisposeListener 
{

    /** The control's shell */
    private Shell fShell;
    /** The control's text widget */
    private StyledText fText;
    /** The control's source viewer */
    private SourceViewer fViewer;
    /** The text font (do not dispose!) */
    private Font fTextFont;
    
    private Document fDocument;
    /**
     * The optional status field.
     */
    private Label fStatusField;
    /**
     * The separator for the optional status field.
     */
    private Label fSeparator;
    /**
     * The font of the optional status text label.
     */
    private Font fStatusTextFont;
    /**
     * The width size constraint.
     */
    private int fMaxWidth= SWT.DEFAULT;
    /**
     * The height size constraint.
     */
    private int fMaxHeight= SWT.DEFAULT;
    /**
     * The orientation of the shell
     */
    private final int fOrientation;

    private Color fBackgroundColor;
    private boolean fIsSystemBackgroundColor= true;

    /**
     * Creates a source viewer information control with the given shell as parent. The given
     * styles are applied to the created styled text widget. The status field will
     * contain the given text or be hidden.
     * 
     * This constructor derives from the original SourceViewerInformationControl class that can be found at
     * org.eclipse.cdt.internal.ui.text.c.hover.SourceViewerInformationControl
     * 
     * It has been modified to be used in Photran hover tool-tip.
     * @author Jungyoon Lee, Kun Koh, Nam Kim, David Weiner
     *
     * @param parent the parent shell
     * @param isResizable <code>true</code> if resizable
     * @param orientation the orientation
     * @param statusFieldText the text to be used in the optional status field
     *            or <code>null</code> if the status field should be hidden
     */
    public SourceViewerInformationControl(Shell parent, boolean isResizable, int orientation, String statusFieldText) 
    {
        Assert.isLegal(orientation == SWT.RIGHT_TO_LEFT || orientation == SWT.LEFT_TO_RIGHT || orientation == SWT.NONE);
        fOrientation= orientation;
        
        GridLayout layout;
        GridData gd;

        int shellStyle = SWT.TOOL | SWT.ON_TOP | orientation | (isResizable ? SWT.RESIZE : 0);
        int textStyle = isResizable ? SWT.V_SCROLL | SWT.H_SCROLL : SWT.NONE;
        
        fShell = new Shell(parent, SWT.NO_FOCUS | SWT.ON_TOP | shellStyle);
        Display display = fShell.getDisplay();

        initializeColors();

        Composite composite = fShell;
        layout = new GridLayout(1, false);
        layout.marginHeight = 0;
        layout.marginWidth = 0;
        composite.setLayout(layout);
        gd = new GridData(GridData.FILL_HORIZONTAL);
        composite.setLayoutData(gd);

        if (statusFieldText != null) 
        {
            composite = new Composite(composite, SWT.NONE);
            layout = new GridLayout(1, false);
            layout.marginHeight= 0;
            layout.marginWidth= 0;
            layout.verticalSpacing= 1;
            composite.setLayout(layout);
            gd= new GridData(GridData.FILL_BOTH);
            composite.setLayoutData(gd);
            composite.setForeground(display.getSystemColor(SWT.COLOR_INFO_FOREGROUND));
            composite.setBackground(fBackgroundColor);
        }

        fViewer = new SourceViewer(composite, null, textStyle);
        fViewer.configure(new FortranEditor.FortranSourceViewerConfiguration(null)
        {
            @Override protected ITokenScanner getStatementTokenScanner()
            {
                // Copied from FortranEditor#getTokenScanner
                return new FortranKeywordRuleBasedScanner(false, fViewer);
            }
        });
               
        fDocument = new Document();
        fDocument.set(""); //$NON-NLS-1$
        fViewer.setDocument(fDocument);
        IDocumentPartitioner partitioner = new FastPartitioner(new FortranStmtPartitionScanner(), FortranStmtPartitionScanner.PARTITION_TYPES);
        partitioner.connect(fDocument);
        fDocument.setDocumentPartitioner(partitioner);
        
        fViewer.setEditable(false);
        fViewer.getTextWidget().setFont(JFaceResources.getTextFont());

        fText= fViewer.getTextWidget();
        gd= new GridData(GridData.BEGINNING | GridData.FILL_BOTH);
        fText.setLayoutData(gd);
        fText.setForeground(display.getSystemColor(SWT.COLOR_INFO_FOREGROUND));
        fText.setBackground(fBackgroundColor);

        initializeFont();
        
        fText.addKeyListener(new KeyListener() 
        {

            public void keyPressed(KeyEvent e)  
            {
                if (e.character == 0x1B) // ESC
                    fShell.dispose();
            }

            public void keyReleased(KeyEvent e) {}
        });

        // Status field
        if (statusFieldText != null) 
        {

            // Horizontal separator line
            fSeparator = new Label(composite, SWT.SEPARATOR | SWT.HORIZONTAL | SWT.LINE_DOT);
            fSeparator.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));

            // Status field label
            fStatusField = new Label(composite, SWT.RIGHT);
            fStatusField.setText(statusFieldText);
            Font font= fStatusField.getFont();
            FontData[] fontDatas = font.getFontData();
            for (int i= 0; i < fontDatas.length; i++)
                fontDatas[i].setHeight(fontDatas[i].getHeight() * 9 / 10);
            fStatusTextFont = new Font(fStatusField.getDisplay(), fontDatas);
            fStatusField.setFont(fStatusTextFont);
            GridData gd2 = new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
            fStatusField.setLayoutData(gd2);

            // Regarding the color see bug 41128
            fStatusField.setForeground(display.getSystemColor(SWT.COLOR_WIDGET_DARK_SHADOW));
            fStatusField.setBackground(fBackgroundColor);
        }

        addDisposeListener(this);

    }

    private void initializeColors() 
    {
        RGB bgRGB= getHoverBackgroundColorRGB();
        if (bgRGB != null) 
        {
            fBackgroundColor = new Color(fShell.getDisplay(), bgRGB);
            fIsSystemBackgroundColor = false;
        } 
        else 
        {
            fBackgroundColor = fShell.getDisplay().getSystemColor(SWT.COLOR_INFO_BACKGROUND);
            fIsSystemBackgroundColor = true;
        }
    }

    private RGB getHoverBackgroundColorRGB() 
    {
        IPreferenceStore store = CUIPlugin.getDefault().getPreferenceStore();
        return store.getBoolean(PreferenceConstants.EDITOR_SOURCE_HOVER_BACKGROUND_COLOR_SYSTEM_DEFAULT)
            ? null
            : PreferenceConverter.getColor(store, PreferenceConstants.EDITOR_SOURCE_HOVER_BACKGROUND_COLOR);
    }

    /**
     * Initialize the font to the editor font.
     */
    private void initializeFont() 
    {
        fTextFont = JFaceResources.getFont(PreferenceConstants.EDITOR_TEXT_FONT);
        StyledText styledText = getViewer().getTextWidget();
        styledText.setFont(fTextFont);
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension2#setInput(java.lang.Object)
     */
    public void setInput(Object input) 
    {
        if (input instanceof String)
            setInformation((String)input);
        else
            setInformation(null);
    }

    /**
     * This method takes information from FortranDeclarationHover
     * then stores it into fDocument.
     * @param content a string that will be displayed in a hover tool-tip.
     */
    public void setInformation(String content) 
    {
        if (content == null)
            return;

        fDocument.set(content);
        fViewer.refresh();
    }

    /*
     * @see IInformationControl#setVisible(boolean)
     */
    public void setVisible(boolean visible) 
    {
        fShell.setVisible(visible);
    }

    /**
     * {@inheritDoc}
     */
    public void widgetDisposed(DisposeEvent event) 
    {
        if (fStatusTextFont != null && !fStatusTextFont.isDisposed())
            fStatusTextFont.dispose();

        fStatusTextFont = null;
        fTextFont = null;
        fShell = null;
        fText = null;
    }

    /**
     * {@inheritDoc}
     */
    public final void dispose() 
    {
        if (!fIsSystemBackgroundColor)
            fBackgroundColor.dispose();
        if (fShell != null && !fShell.isDisposed())
            fShell.dispose();
        else
            widgetDisposed(null);
    }

    /*
     * @see IInformationControl#setSize(int, int)
     */
    public void setSize(int width, int height) 
    {
        fShell.setSize(width, height);
    }

    /*
     * @see IInformationControl#setLocation(Point)
     */
    public void setLocation(Point location) 
    {
        fShell.setLocation(location);
    }

    /*
     * @see IInformationControl#setSizeConstraints(int, int)
     */
    public void setSizeConstraints(int maxWidth, int maxHeight) 
    {
        fMaxWidth = maxWidth;
        fMaxHeight = maxHeight;
    }

    /*
     * @see IInformationControl#computeSizeHint()
     */
    public Point computeSizeHint() 
    {
        // compute the preferred size
        int x = SWT.DEFAULT;
        int y = SWT.DEFAULT;
        Point size = fShell.computeSize(x, y);
        if (size.x > fMaxWidth)
            x = fMaxWidth;
        if (size.y > fMaxHeight)
            y = fMaxHeight;

        // recompute using the constraints if the preferred size is larger than the constraints
        if (x != SWT.DEFAULT || y != SWT.DEFAULT)
            size = fShell.computeSize(x, y, false);

        return size;
    }

    /*
     * @see IInformationControl#addDisposeListener(DisposeListener)
     */
    public void addDisposeListener(DisposeListener listener) 
    {
        fShell.addDisposeListener(listener);
    }

    /*
     * @see IInformationControl#removeDisposeListener(DisposeListener)
     */
    public void removeDisposeListener(DisposeListener listener) 
    {
        fShell.removeDisposeListener(listener);
    }

    /*
     * @see IInformationControl#setForegroundColor(Color)
     */
    public void setForegroundColor(Color foreground) 
    {
        fText.setForeground(foreground);
    }

    /*
     * @see IInformationControl#setBackgroundColor(Color)
     */
    public void setBackgroundColor(Color background) 
    {
        fText.setBackground(background);
    }

    /*
     * @see IInformationControl#isFocusControl()
     */
    public boolean isFocusControl() 
    {
        return fShell.getDisplay().getActiveShell() == fShell;
    }

    /*
     * @see IInformationControl#setFocus()
     */
    public void setFocus() 
    {
        fShell.forceFocus();
        fText.setFocus();
    }

    /*
     * @see IInformationControl#addFocusListener(FocusListener)
     */
    public void addFocusListener(FocusListener listener) 
    {
        fText.addFocusListener(listener);
    }

    /*
     * @see IInformationControl#removeFocusListener(FocusListener)
     */
    public void removeFocusListener(FocusListener listener) 
    {
        fText.removeFocusListener(listener);
    }

    /*
     * @see IInformationControlExtension#hasContents()
     */
    public boolean hasContents() 
    {
        return fText.getCharCount() > 0;
    }

    protected ISourceViewer getViewer()  
    {
        return fViewer;
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension3#computeTrim()
     */
    public Rectangle computeTrim()
    {
        Rectangle trim = fShell.computeTrim(0, 0, 0, 0);
        addInternalTrim(trim);
        return trim;
    }

    /**
     * Adds the internal trimmings to the given trim of the shell.
     * 
     * @param trim the shell's trim, will be updated
     */
    private void addInternalTrim(Rectangle trim) 
    {
        Rectangle textTrim = fText.computeTrim(0, 0, 0, 0);
        trim.x += textTrim.x;
        trim.y += textTrim.y;
        trim.width += textTrim.width;
        trim.height += textTrim.height;
        
        if (fStatusField != null) 
        {
            trim.height += fSeparator.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
            trim.height += fStatusField.computeSize(SWT.DEFAULT, SWT.DEFAULT).y;
            trim.height += 1; // verticalSpacing
        }
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension3#getBounds()
     */
    public Rectangle getBounds() 
    {
        return fShell.getBounds();
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension3#restoresLocation()
     */
    public boolean restoresLocation() 
    {
        return false;
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension3#restoresSize()
     */
    public boolean restoresSize() 
    {
        return false;
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension5#getInformationPresenterControlCreator()
     */
    public IInformationControlCreator getInformationPresenterControlCreator() 
    {
        return new IInformationControlCreator() 
        {
            public IInformationControl createInformationControl(Shell parent) 
            {
                return new SourceViewerInformationControl(parent, true, fOrientation, null);
            }
        };
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension5#containsControl(org.eclipse.swt.widgets.Control)
     */
    public boolean containsControl(Control control) 
    {
        do {
            if (control == fShell)
                return true;
            if (control instanceof Shell)
                return false;
            control= control.getParent();
        } while (control != null);
        return false;
    }

    /*
     * @see org.eclipse.jface.text.IInformationControlExtension5#isVisible()
     */
    public boolean isVisible() 
    {
        return fShell != null && !fShell.isDisposed() && fShell.isVisible();
    }
    
    /*
     * @see org.eclipse.jface.text.IInformationControlExtension5#computeSizeConstraints(int, int)
     */
    public Point computeSizeConstraints(int widthInChars, int heightInChars) 
    {
        GC gc= new GC(fText);
        gc.setFont(fTextFont);
        int width = gc.getFontMetrics().getAverageCharWidth();
        int height = gc.getFontMetrics().getHeight();
        gc.dispose();

        return new Point(widthInChars * width, heightInChars * height);
    }

}
